Nine Months of DevEx Improvement at Mercari Group

Mercari Group implemented a company-wide DevEx improvement initiative over nine months, evolving from team-level efforts with mixed results to a dual-layer approach combining bottom-up team improvements with top-down organizational policies. The breakthrough came in Phase 2 when VPoE-led initiatives focused on Deep Work achieved 16% improvement in a single quarter by establishing clear policies like no-meeting time blocks and meeting consolidation. Success required three key roles (Executive Sponsor, Champion, Manager), proper structure with 6-12 month timebases, and connecting developer pain to business outcomes. Ongoing challenges include horizontal deployment across diverse organizations, measuring long-term business impact, and maintaining momentum across multiple quarters.